<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
    <style>
        *{
            margin: 0px;
            padding: 0px;
        }
        .mant{
            width: 300px;
            height: 50px;
            background-color: yellowgreen;
            text-align: center;

        }
        #mant:hover{
            position: relative;
            top: 0px;

        }
        span{
            color: white;
            font-size: 20px;
            line-height: 50px;

        }
        .xuxian{
            height: 300px;
            width: 300px;
            background-color: wheat;
            position:relative;
            top: -300px;
            z-index: -1px;
            transition: 1s;
        }
        .inte1{
            border-left-width: 0px;
        }
    </style>
</head>
<body>
    <div id="mant">
        <span>菜单选项</span>
        <div id="xuxian">
                <div class="inte"><span>选项</span></div>
                <div class="inte"><span>选项</span></div>
                <div class="inte"><span>选项</span></div>
                <div class="inte"><span>选项</span></div>
                <div class="inte"><span>选项</span></div>
                <div class="inte"><span>选项</span>
                    <div class="inte1">二级标签</div>
                </div>
                
                    <div class="inte1">二级标签</div>

        </div>
    </div>
</body>
</html>